Short answer
Hepatitis B and hepatitis C testing are blood tests that may be part of sexual health care, but they are not included in every STI panel. CDC recommends hepatitis B screening for all adults 18 and older at least once and periodic testing for people with risk factors, including people with STIs or multiple sex partners. CDC also recommends hepatitis C screening for all adults 18 and older at least once and for all pregnant women during each pregnancy, with more frequent testing for some ongoing risks.
How hepatitis B and C differ
| Topic | Hepatitis B | Hepatitis C |
|---|---|---|
| Can it spread sexually? | Yes. CDC says hepatitis B can be transmitted through sexual activity, especially with an infected partner, multiple sex partners, MSM exposure, other STIs, or injection-drug use. | Less efficiently through sex, but sexual transmission can occur, especially with HIV, multiple partners, anal sex, traumatic sexual practices, or STI-related proctitis. |
| Is there a vaccine? | Yes. Vaccination is the most effective prevention tool. | No vaccine is available. |
| Common screening approach | CDC recommends a hepatitis B triple panel: HBsAg, anti-HBs, and total anti-HBc. | CDC recommends an HCV antibody test, followed by HCV RNA testing if the antibody result is positive or reactive. |
| What positive testing may mean | Results can suggest current infection, resolved past infection, vaccine-related immunity, or susceptibility. | A reactive antibody can mean past or current infection; HCV RNA is needed to diagnose current infection. |
| Pregnancy | CDC recommends hepatitis B testing early in each pregnancy. | CDC recommends hepatitis C testing during each pregnancy, except in very low-prevalence settings. |
Why hepatitis B testing can involve three markers
Hepatitis B testing is not just one yes-or-no result. CDC's recommended triple panel includes HBsAg, anti-HBs, and total anti-HBc. Together, these markers can help distinguish current infection, prior infection, immunity after vaccination, and susceptibility. If you only see one hepatitis B result on a portal, ask whether a full triple panel was done.
Why hepatitis C testing often has two steps
CDC says clinicians should use an FDA-approved HCV antibody test followed by a nucleic acid test for HCV RNA when the antibody test is positive or reactive. The antibody result can stay positive after a past infection clears or is treated, so RNA testing is what confirms current infection.
When hepatitis testing belongs in an STI conversation
- You are getting a broad STI panel and want to know whether hepatitis B or C is included.
- You have had multiple sex partners, a partner with hepatitis B, a recent STI, or injection-drug equipment exposure.
- You are pregnant, planning pregnancy, or starting prenatal care.
- You are using HIV PrEP, discussing DoxyPEP, testing after a new partner, or testing after vacation or travel sex.
- You have HIV, abnormal liver tests, or a history of hepatitis C risk factors.
- You do not know whether you completed hepatitis B vaccination or whether you are immune.
What a full STI panel may miss
A panel labeled "full" might include HIV, syphilis, chlamydia, and gonorrhea but not hepatitis B or C. It may include hepatitis C antibody but not reflex RNA testing, or hepatitis B surface antigen without the full triple panel. Ask for the exact test names. For broader panel questions, see the full STI panel guide.
How this connects to liver blood tests
Liver enzyme tests such as ALT and AST can show liver irritation or injury, but they do not diagnose hepatitis B or C by themselves. Hepatitis testing looks for viral markers or viral RNA. If liver enzymes are abnormal, ask whether hepatitis testing, alcohol history, medication review, imaging, or other follow-up is needed. See the liver function tests guide.
Questions to ask before testing
- Does this STI panel include hepatitis B, hepatitis C, both, or neither?
- For hepatitis B, is this the triple panel: HBsAg, anti-HBs, and total anti-HBc?
- For hepatitis C, will a positive antibody result automatically reflex to HCV RNA testing?
- Do I need hepatitis B vaccination or proof of immunity?
- Should I repeat testing because of pregnancy, HIV, injection-drug equipment exposure, or ongoing sexual risk?
- If a result is positive, who handles confirmatory testing, treatment referral, reporting, and partner or household guidance?
Related Lab Intel guides
For general sexual health screening, start with the STI testing guide. For PrEP-related lab monitoring, see the PrEP labs and STI testing follow-up guide. For pregnancy-specific screening, see the STI testing for pregnancy planning guide. For affordable testing sites, see the free and low-cost STI testing guide. For timing after a new partner, see the STI testing after a new partner guide. For travel-specific vaccine and follow-up questions, see the STI testing after vacation or travel sex guide.